diff --git a/python/paddle/fluid/layer_helper.py b/python/paddle/fluid/layer_helper.py
index e0fd44ae31e3e66adfb8d5dd8a21051c48d24afa..ea9953f5814207c569e799c2ffa11758e31699aa 100644
--- a/python/paddle/fluid/layer_helper.py
+++ b/python/paddle/fluid/layer_helper.py
@@ -405,7 +405,8 @@ class LayerHelper(object):
         """
         size = list(input_var.shape[dim_start:dim_end])
         bias_attr = self.bias_attr
-        assert bias_attr is not None
+        if not bias_attr:
+            return input_var
 
         b = self.create_parameter(
             attr=bias_attr, shape=size, dtype=input_var.dtype, is_bias=True)